Restoring x server zap functionality

The xorg x server on gentoo has the ctrl-alt-backspace disabled by default. I really like that functionality (especially when seeing that there is a lot of memory in use when nothing is running, after a very long uptime).

Apparently you should use kernel SAK which is superior (alt-break-K if you have magic sysrq configured in the kernel). For some reason it is not recommended to use this to SAK, so a new key sequence should be defined for it. A good place to do it in gentoo is in /etc/conf.d/local.start, and since ctrl-alt-backspace is available, it can be used for this purpose (key code 14):

# Set ctrl-alt-backspace to SAK
echo "control alt keycode 14 = SAK" | /usr/bin/loadkeys

Optionally restore the key map in /etc/conf.d/local.stop:

# restore keymap to default
/usr/bin/loadkeys --default

It is also a good place to set a replacement key sequence for reboot, if ctrl-alt-del is disabled in /etc/inittab. For example ctrl-alt-break (key code 119):

echo "control alt keycode 119 = Boot" | /usr/bin/loadkeys